Light-emitting device and aromatic compound

ABSTRACT

A light-emitting device comprising a pair of electrodes and a light-emitting layer or a plurality of organic layers comprising a light-emitting layer disposed therebetween, the light-emitting layer or at least one of a plurality of organic layers comprising the light-emitting layer comprising at least one compound represented by the following general formula (1): wherein each of Ar 11 , Ar 12 , Ar 13 , Ar 14  and Ar 15  represents an aryl group or a heteroaryl group; Ar represents a benzene ring, a naphthalene ring, a phenanthrene ring or an anthracene ring; at least one of Ar, Ar 11 , Ar 12 , Ar 13 , Ar 14  and Ar 15  is a condensed aryl group, a condensed or uncondensed heteroaryl group or a group comprising a condensed aryl group or a condensed or uncondensed heteroaryl group; Ar 11 , Ar 12 , Ar 13 , Ar 14  and Ar 15  are not bonded to each other to form a ring; R 11  represents a substituent; and n 11  represents an integer of 0 or more.

FIELD OF THE INVENTION

The present invention relates to a light-emitting device that convertselectric energy to light, particularly to a light-emitting devicesuitable for indicating elements, displays, backlights,electrophotography, illumination light sources, recording light sources,exposing light sources, reading light sources, signs and marks,signboards, interiors, optical communications devices, etc., and a novelaromatic compound usable for such a light-emitting device.

BACKGROUND OF THE INVENTION

Various display devices have been actively researched and developed inrecent years. In particular, organic electroluminescence (EL) devicesattract much attention because they can emit light at a high luminancewith low voltage applied. For example, a light-emitting devicecomprising organic thin layers provided by vapor-depositing organiccompounds is disclosed in Applied Physics Letters, Vol. 51, page 913(1987). This light-emitting device has a structure where anelectron-transporting material of tris(8-hydroxyquinolinato) aluminumcomplex (Alq) and a hole-transporting material of an amine compound aredisposed between electrodes as a laminate, thereby exhibiting moreexcellent light-emitting properties than those of conventionallight-emitting devices having a single-layer structure.

Active research and development have been made to apply organic ELdevices to fill-color displays in recent years. To providehigh-performance, full-color displays, light-emitting properties shouldbe improved for each of blue, green and red colors. For instance,blue-color, light-emitting devices are disadvantageous in color purity,durability, light-emitting luminance and light-emitting efficiency, andthus their improvement is desired. To solve these problems, devicescomprising aromatic condensed-ring compounds were investigated (JP11-12205 A, etc.), but there is still a problem that such light-emittingdevices are low in light-emitting efficiency, failing to emit blue lightwith high color purity. In addition, improvement is desired in organicEL devices, too.

OBJECT OF THE INVENTION

An object of the present invention is to provide a light-emitting deviceexcellent in light-emitting properties and durability.

Another object of the present invention is to provide an aromaticcompound excellent in color purity and durability, and usable for suchlight-emitting devices.

DISCLOSURE OF THE INVENTION

As a result of intense research in view of the above objects, theinventors have found that a light-emitting device comprising an aromaticcompound having a particular structure is excellent in light-emittingproperties and durability. The present invention has been completedbased on this finding.

Thus, the light-emitting device of the present invention comprises apair of electrodes and a light-emitting layer or a plurality of organiclayers comprising a light-emitting layer disposed between theelectrodes, either of the light-emitting layer or at least one of aplurality of organic layers comprising a light-emitting layer comprisingat least one compound represented by the general formula (1):

wherein each of Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ represents an aryl groupor a heteroaryl group; Ar represents a benzene ring, a naphthalene ring,a phenanthrene ring or an anthracene ring; at least one of Ar, Ar¹¹,Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ is a condensed aryl group, a condensed oruncondensed heteroaryl group or a group comprising a condensed arylgroup or a condensed or uncondensed heteroaryl group; Ar¹¹, Ar¹², Ar¹³,Ar¹⁴ and Ar¹⁵ are not bonded to each other to form a ring; R¹¹represents a substituent; and n¹¹ represents an integer of 0 or more.

In the general formula (1), at least one of Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ andAr¹⁵ is a pyrenyl group.

In the above general formula (1), at least four of R¹¹, Ar¹¹, Ar¹²,Ar¹³, Ar¹⁴ and Ar¹⁵ are preferably a condensed aryl group or a condensedor uncondensed heteroaryl group, more preferably a condensed aryl group,most preferably a phenanthryl group or a pyrenyl group.

In the above general formula (1), at least one of R¹¹, Ar¹¹, Ar¹², Ar¹³,Ar¹⁴ and Ar¹⁵ is selected from the group consisting of a naphthyl group,a phenanthryl group, an anthryl group, a fluoranthenyl group, a pyrenylgroup and a perylenyl group, more preferably a naphthyl group or aphenanthryl group.

The compound represented by the general formula (1) preferably emitslight from a singlet excited state.

The first preferred example of the general formula (1) is the followinggeneral formula (2):

wherein each of Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ represents an aryl groupor a heteroaryl group; at least one of Ar²¹, Ar²², Ar²⁴ and Ar²⁵ is acondensed aryl group, a condensed or uncondensed heteroaryl group or agroup comprising a condensed aryl group or a condensed or uncondensedheteroaryl group; Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ are not bonded to eachother to form a ring; R²¹ represents a hydrogen atom or a substituent.

In the general formula (2), it is preferable that each of Ar²¹, Ar²²,Ar²³ and Ar²⁴ is selected from the group consisting of a phenyl group, anaphthyl group, an anthryl group, a phenanthryl group and afluoranthenyl group; Ar²⁵ is selected from the group consisting of aphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, afluoranthenyl group, a pyrenyl group and a perylenyl group; R²¹ isselected from the group consisting of a hydrogen atom, an alkyl groupand an aryl group; at least one of Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ is acondensed aryl group; Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ are not bonded toeach other to form a ring.

In the general formula (2), each of Ar²¹, Ar²², Ar²³ and Ar²⁴ is morepreferably selected from the group consisting of a phenyl group, anaphthyl group and a phenanthryl group, most preferably a phenyl group.

In the general formula (2), Ar²⁵ is more preferably selected from thegroup consisting of an anthryl group, a phenanthryl group, afluoranthenyl group, a pyrenyl group and a perylenyl group.

In the general formula (2), R²¹ is more preferably selected from thegroup consisting of a hydrogen atom, a phenyl group and a pyrenyl group.

In the above general formula (2), at least four of R²¹, Ar²¹, Ar²²,Ar²³, Ar²⁴ and Ar²⁵ are preferably a condensed aryl group or a condensedor uncondensed heteroaryl group, more preferably a condensed aryl group,most preferably a phenanthryl group or a pyrenyl group.

In the above general formula (2), each of Ar²¹ and Ar²² is a condensedaryl group or a condensed or uncondensed heteroaryl group, morepreferably a condensed aryl group, most preferably a phenanthryl groupor a pyrenyl group.

In the above general formula (2), each of Ar²¹ and Ar²⁴ is preferably acondensed aryl group or a condensed or uncondensed heteroaryl group,more preferably a condensed aryl group, most preferably a phenanthrylgroup or a pyrenyl group.

In the above general formula (2), at least one of R¹¹, Ar¹¹, Ar¹², Ar¹³,Ar¹⁴ and Ar¹⁵ is selected from the group consisting of a naphthyl group,a phenanthryl group, an anthryl group, a fluoranthenyl group, a pyrenylgroup and a perylenyl group, more preferably a naphthyl group or aphenanthryl group.

In the above general formula (2), it is preferable that each of Ar²¹ andAr²³ is a condensed aryl group, and that each of R²¹, Ar²², Ar²⁴ andAr²⁵ is selected from the group consisting of a phenyl group, a naphthylgroup, a phenanthryl group, an anthryl group, a fluoranthenyl group, apyrenyl group and a perylenyl group; and it is more preferable that eachof Ar²¹ and Ar²³ is a pyrenyl group, and that each of R²¹, Ar²², Ar²⁴and Ar²⁵ is selected from the group consisting of a phenyl group, anaphthyl group and a phenanthryl group.

The first preferred example of the general formula (2) is the followinggeneral formula (5):

wherein each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴ represents an aryl group, R⁵¹represents a hydrogen atom or a substituent, R⁵² represents asubstituent, and n⁵¹ is an integer of 0 to 9.

In the general formula (5), each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴ ispreferably selected from the group consisting of a phenyl group, anaphthyl group, an anthryl group, a phenanthryl group and afluoranthenyl group, more preferably a phenyl group.

In the general formula (5), R⁵¹ is preferably selected from the groupconsisting of a hydrogen atom, an alkyl group and an aryl group, morepreferably selected from the group consisting of a hydrogen atom, aphenyl group and a pyrenyl group, most preferably a phenyl group or apyrenyl group.

The second preferred example of the general formula (2) is the followinggeneral formula (6):

wherein each of Ar⁶¹, Ar⁶², Ar⁶³, Ar⁶⁴, Ar⁶⁵, Ar⁶⁶, Ar⁶⁷ and Ar⁶⁸represents an aryl group or a heteroaryl group; each of R⁶¹ and R⁶²represents a hydrogen atom or a substituent; each of R⁶³, R⁶⁴ and R⁶⁵represents a substituent; each of n⁶¹ and n⁶² is an integer of 0 to 5;each of n⁶³ and n⁶⁴ is an integer of 0 to 4; and n⁶⁵ is an integer of 0to 8.

In the general formula (6), each of Ar⁶¹, Ar⁶², Ar⁶³, Ar⁶⁴, Ar⁶⁵, Ar⁶⁶,Ar⁶⁷ and Ar⁶⁸ is preferably selected from the group consisting of aphenyl group, a naphthyl group and a phenanthryl group. In particular,each of R⁶¹ and R⁶² is preferably selected from the group consisting ofa hydrogen atom, a phenyl group and a pyrenyl group. Each of n⁶¹ and n⁶²is preferably 0 or 1.

The second preferred example of the general formula (1) is the followinggeneral formula (3):

wherein each of Ar³¹, Ar³², Ar³³, Ar³⁴, Ar³⁵, Ar³⁶, Ar³⁷ and Ar³⁸represents an aryl group or a heteroaryl group; and Ar³¹, Ar³², Ar³³,Ar³⁴, Ar³⁵, Ar³⁶, Ar³⁷ and Ar³⁸ are not bonded to each other to form aring.

In the general formula (3), each of Ar³¹, Ar³², Ar³³, Ar³⁴, Ar³⁵, Ar³⁶,Ar³⁷ and Ar³⁸ is preferably an aryl group, more preferably selected fromthe group consisting of a phenyl group, a naphthyl group, an anthrylgroup, a phenanthryl group and a pyrenyl group, most preferably a phenylgroup.

The third preferred example of the general formula (1) is the followinggeneral formula (4):

wherein each of Ar⁴¹, Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶, Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ andAr⁵⁰ represents an aryl group or a heteroaryl group; and Ar⁴¹, Ar⁴²,Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶, Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ and Ar⁵⁰ are not bonded to eachother to form a ring.

In the general formula (4), each of Ar⁴¹, Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶,Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ and Ar⁵⁰ is preferably an aryl group, more preferablyselected from the group consisting of a phenyl group, a naphthyl group,an anthryl group, a phenanthryl group and a pyrenyl group, mostpreferably a phenyl group.

The compound of the general formula (1) is preferably represented by anyone of the above general formulae (2)-(4), more preferably representedby the general formula (2).

The content of the compound represented by the general formula (1) inthe light-emitting layer is preferably 0.1 to 100% by mass as alight-emitting material.

The content of the compound represented by the general formula (1) inthe light-emitting layer or at least one of a plurality of organiclayers comprising the light-emitting layer is preferably 10 to 99.9% bymass as a host material.

At least one of the above light-emitting layer and a plurality oforganic layers comprising the above light-emitting layer is preferably alight-emitting layer.

At least one of the above light-emitting layer and a plurality oforganic layers comprising the above light-emitting layer is preferably ahole-transporting layer.

The above light-emitting layer preferably comprises at least onefluorescent compound.

The aromatic compound of the present invention is represented by thegeneral formula (5):

wherein each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴ represents an aryl group; R⁵¹represents a hydrogen atom or a substituent; R⁵² represents asubstituent; and n⁵¹ is an integer of 0 to 9.

In the general formula (5), each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴ ispreferably selected from the group consisting of a phenyl group, anaphthyl group, an anthryl group, a phenanthryl group and afluoranthenyl group, more preferably a phenyl group.

In the general formula (5), R⁵¹ is preferably selected from the groupconsisting of a hydrogen atom, an alkyl group and an aryl group, morepreferably selected from the group consisting of a hydrogen atom, aphenyl group and a pyrenyl group, most preferably a phenyl group or apyrenyl group.

The aromatic compound represented by the general formula (5) is apreferred example of the compound represented by the general formula(2), which can preferably be used as the compound represented by thegeneral formula (1).

BEST MODE FOR CARRYING OUT THE INVENTION

The light-emitting device of the present invention comprises a pair ofelectrodes and a light-emitting layer and a plurality of organic layerscomprising a light-emitting layer disposed therebetween. Thelight-emitting layer or at least one layer in a plurality of organiclayers comprising the light-emitting layer comprises at least onecompound represented by the following general formula (1). The compoundrepresented by any one of the general formulae (1)-(6) may be referredto as “compound (1)” or “compound of the present invention” hereinafter.

In the general formula (1), each of Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵represents an aryl group or a heteroaryl group. Examples of the arylgroups include a phenyl group, a naphthyl group, an anthryl group, aphenanthryl group, a fluoranthenyl group, a pyrenyl group, a perylenylgroup, a chrysenyl group, a triphenylenyl group, a benzoanthryl group, abenzophenanthryl group, etc. Preferable among them are a phenyl group, anaphthyl group, an anthryl group, a phenanthryl group, a pyrenyl groupand a perylenyl group. Examples of the condensed or uncondensedheteroaryl groups include a pyridyl group, a quinolyl group, aquinoxalyl group, a quinazolyl group, an acridyl group, a phenanthridylgroup, a phthalazyl group, a phenanthrolyl group, a triazyl group, etc.Preferable among them are a pyridyl group, a quinolyl group and atriazyl group. Each of Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ may have asubstituent, whose examples may be the same as those of R¹¹ describedlater. Each of Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ is preferably an arylgroup. Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ are not bonded to each other toform a ring.

In the general formula (1), Ar represents a benzene ring, a naphthalenering, a phenanthrene ring or an anthracene ring. Ar is preferably abenzene ring or a naphthalene ring, more preferably a benzene ring.

At least one of Ar, Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵ is a condensed arylgroup or a group comprising a condensed aryl group, such as a naphthylgroup, a phenanthryl group, an anthryl group, a pyrenyl group, aperylenyl group, a fluoranthenyl group, etc.; or a condensed oruncondensed heteroaryl group or a group comprising a condensed oruncondensed heteroaryl group, such as a pyridyl group, a quinolyl group,a quinoxalyl group, a quinazolyl group, an acridyl group, aphenanthridyl group, a phthalazyl group, a phenanthrolyl group, atriazyl group, etc. At least one of Ar, Ar¹¹, Ar¹², Ar¹³, Ar¹⁴ and Ar¹⁵is preferably a condensed aryl group or a group comprising a condensedaryl group, more preferably a pyrenyl group. The number of pyrenylgroups m the compound (1) is preferably two or less. The above groupcomprising a condensed aryl group or a condensed or uncondensedheteroaryl group may be composed of a condensed aryl group or acondensed or uncondensed heteroaryl group, and an alkylene group, anarylene group, etc., though it is preferably composed of only acondensed aryl group or a condensed or uncondensed heteroaryl group.

In the general formula (1), R¹¹ represents a substituent. Examples ofthe substituents R¹¹ include alkyl groups, the number of carbon atomsthereof being preferably 1 to 30, more preferably 1 to 20, mostpreferably 1 to 10, such as a methyl group, an ethyl group, an isopropylgroup, a t-butyl group, a n-octyl group, a n-decyl group, a n-hexadecylgroup, a cyclopropyl group, a cyclopentyl group and a cyclohexyl group;alkenyl groups, the number of carbon atoms thereof being preferably 2 to30, more preferably 2 to 20, most preferably 2 to 10, such as a vinylgroup, an allyl group, a 2-butenyl group and a 3-pentenyl group; alkynylgroups, the number of carbon atoms thereof being preferably 2 to 30,more preferably 2 to 20, most preferably 2 to 10, such as a propargylgroup and a 3-pentynyl group; aryl groups, the number of carbon atomsthereof being preferably 6 to 30, more preferably 6 to 20, mostpreferably 6 to 12, such as a phenyl group, a p-methylphenyl group, anaphthyl group and an anthranil group; amino groups, the number ofcarbon atoms thereof being preferably 0 to 30, more preferably 0 to 20,most preferably 0 to 10, such as an amino group, a methylamino group, adimethylamino group, a diethylamino group, a dibenzylamino group, adiphenylamino group and a ditolylamino group; alkoxy groups, the numberof carbon atoms thereof being preferably 1 to 30, more preferably 1 to20, most preferably 1 to 10, such as a methoxy group, an ethoxy group, abutoxy group and a 2-ethylhexyloxy group; aryloxy groups, the number ofcarbon atoms thereof being preferably 6 to 30, more preferably 6 to 20,most preferably 6 to 12, such as a phenyloxy group, a 1-naphthyloxygroup and a 2-naphthyloxy group; heterocyclicoxy groups, the number ofcarbon atoms thereof being preferably 1 to 30, more preferably 1 to 20,most preferably 1 to 12, such as a pyridyloxy group, a pyrazyloxy group,a pyrimidyloxy group and a quinolyloxy group; acyl groups, the number ofcarbon atoms thereof being preferably 1 to 30, more preferably 1 to 20,most preferably 1 to 12, such as an acetyl group, a benzoyl group, aformyl group and a pivaloyl group; alkoxycarbonyl groups, the number ofcarbon atoms thereof being preferably 2 to 30, more preferably 2 to 20,most preferably 2 to 12, such as a methoxycarbonyl group and anethoxycarbonyl group; aryloxycarbonyl groups, the number of carbon atomsthereof being preferably 7 to 30, more preferably 7 to 20, mostpreferably 7 to 12, such as a phenyloxycarbonyl group; acyloxy groups,the number of carbon atoms thereof being preferably 2 to 30, morepreferably 2 to 20, most preferably 2 to 10, such as an acetoxy groupand a benzoyloxy group; acylamino groups, the number of carbon atomsthereof being preferably 2 to 30, more preferably 2 to 20, mostpreferably 2 to 10, such as an acetylamino group and a benzoylaminogroup; alkoxycarbonylamino groups, the number of carbon atoms thereofbeing preferably 2 to 30, more preferably 2 to 20, most preferably 2 to12, such as a methoxycarbonylamino group; aryloxycarbonylamino groups,the number of carbon atoms thereof being preferably 7 to 30, morepreferably 7 to 20, most preferably 7 to 12, such as aphenyloxycarbonylamino group; sulfonylamino groups, the number of carbonatoms thereof being preferably 1 to 30, more preferably 1 to 20, mostpreferably 1 to 12, such as a methanesulfonylamino group and abenzenesulfonylamino group; sulfamoyl groups, the number of carbon atomsthereof being preferably 0 to 30, more preferably 0 to 20, mostpreferably 0 to 12, such as a sulfamoyl group, a methylsulfamoyl group,a dimethylsulfamoyl group and a phenylsulfamoyl group; carbamoyl groups,the number of carbon atoms thereof being preferably 1 to 30, morepreferably 1 to 20, most preferably 1 to 12, such as a carbamoyl group,a methylcarbamoyl group, a diethylcarbamoyl group, a phenylcarbamoylgroup; alkylthio groups, the number of carbon atoms thereof beingpreferably 1 to 30, more preferably 1 to 20, most preferably 1 to 12,such as a methylthio group and an ethylthio group; arylthio groups, thenumber of carbon atoms thereof being preferably 6 to 30, more preferably6 to 20, most preferably 6 to 12, such as a phenylthio group;heterocyclic thio groups, the number of carbon atoms thereof beingpreferably 1 to 30, more preferably 1 to 20, most preferably 1 to 12,such as a pyridylthio group, a 2-benzimidazolylthio group, a2-benzoxazolylthio group and a 2-benzthiazolylthio group; sulfonylgroups, the number of carbon atoms thereof being preferably 1 to 30,more preferably 1 to 20, most preferably 1 to 12, such as a mesyl groupand a tosyl group; sulfinyl groups, the number of carbon atoms thereofbeing preferably 1 to 30, more preferably 1 to 20, most preferably 1 to12, such as a methane sulfinyl group and a benzene sulfinyl group;ureide groups, the number of carbon atoms thereof being preferably 1 to30, more preferably 1 to 20, most preferably 1 to 12, such as a ureidegroup, a methylureide group and a phenylureide group; phosphoric amidegroups, the number of carbon atoms thereof being preferably 1 to 30,more preferably 1 to 20, most preferably 1 to 12, such as adiethylphosphoric amide group and a phenylphosphoric amide group; ahydroxyl group; mercapto groups; halogen atoms such as a fluorine atom,a chlorine atom, a bromine atom and an iodine atom; cyano groups; sulfogroups; carboxyl groups; nitro groups; a hydroxamic acid group; asulfino group; a hydrazino group; an imino group; heterocyclic groupsthat may have a nitrogen atom, a oxygen atom, a sulfur atom, etc. as ahetero atom, the number of carbon atoms thereof being preferably 1 to30, more preferably 1 to 12, such as an imidazolyl group, a pyridylgroup, a quinolyl group, a furyl group, a thienyl group, a piperidylgroup, a morpholino group, a benzoxazolyl group, a benzimidazolyl group,a benzthiazolyl group, a carbazolyl group, an azepinyl group and atriazyl group; silyl groups, the number of carbon atoms thereof beingpreferably 3 to 40, more preferably 3 to 30, most preferably 3 to 24,such as a trimethylsilyl group and a triphenylsilyl group; siloxygroups, the number of carbon atoms thereof being preferably 3 to 30,more preferably 6 to 30, such as a triphenylsilyloxy group, at-butyldimethylsilyloxy group; etc. These substituents may be furthersubstituted. R¹¹ is preferably an alkyl group or an aryl group.

In the general formula (1), n¹¹ represents an integer of 0 or more,preferably 0 to 5, more preferably 0 to 2, most preferably 1.

From the viewpoint of vapor depositability during the production of thelight-emitting device, the number of benzene rings in the compound (1)is preferably 15 or less. Also, when the compound (1) comprises acondensed group having four or more rings, such as a pyrene group, atriphenylene group, etc., the number of the condensed group having fouror more rings is preferably 2 or less.

The compound (1) is represented preferably by the following generalformula (2), (3) or (4), more preferably by the general formula (2),further preferably by the following general formula (5) or (6), mostpreferably by the general formula (5). The compound represented by thegeneral formula (4) is preferably represented by the following generalformula (6).

In the general formula (2), each of Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵represents an aryl group or a heteroaryl group, preferably an arylgroup. Each of Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ may have a substituent.Examples of the substituents may be the same as those of R¹¹ describedabove. At least one of Ar²¹, Ar²², Ar²³, Ar²⁴ and Ar²⁵ is a condensedaryl group, a condensed or uncondensed heteroaryl group or a groupcomprising a condensed aryl group or a condensed or uncondensedheteroaryl group. Each of Ar²¹, Ar²², Ar²³ and Ar²⁴ is preferably aphenyl group, a naphthyl group, an anthryl group, a phenanthryl group ora fluoranthenyl group, more preferably a phenyl group, a naphthyl group,an anthryl group or a phenanthryl group, further preferably a phenylgroup, a naphthyl group or a phenanthryl group, most preferably a phenylgroup. Ar²⁵ is preferably a phenyl group, a naphthyl group, aphenanthryl group, an anthryl group, a pyrenyl group, a perylenyl groupor a fluoranthenyl group, more preferably a phenanthryl group, ananthryl group or a pyrenyl group, most preferably a pyrenyl group. Ar²¹,Ar²², Ar²³, Ar²⁴ and Ar²⁵ are not bonded to each other to form a ring.

In the general formula (2), R²¹ represents a hydrogen atom or asubstituent. Examples of the substituents may be the same as those ofR¹¹ described above. R²¹ is preferably a hydrogen atom, an alkyl groupor an aryl group, more preferably a hydrogen atom, a phenyl group or apyrenyl group, most preferably a pyrenyl group.

In the general formula (3), each of Ar³¹, Ar³², Ar³³, Ar³⁴, A³⁵, Ar³⁶,Ar³⁷ and Ar³⁸ represents an aryl group or a heteroaryl group. Each ofAr³¹, Ar³², Ar³³, Ar³⁴, Ar³⁵, Ar³⁶, Ar³⁷ and Ar³⁸ may have asubstituent, whose examples maybe the same as those of R¹¹ describedabove. Ar³¹, Ar³², Ar³³, Ar³⁴, Ar³⁵, Ar³⁶, Ar³⁷ and Ar³⁸ are not bondedto each other to form a ring. Each of Ar³¹, Ar³², Ar³³, Ar³⁴, Ar³⁵,Ar³⁶, Ar³⁷ and Ar³⁸ is preferably an aryl group, more preferably aphenyl group, a naphthyl group, an anthryl group, a pyrenyl group or aphenanthryl group, most preferably a phenyl group.

In the general formula (4), each of Ar⁴¹, Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶,Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ and Ar⁵⁰ represents an aryl group or a heteroarylgroup. Each of Ar⁴¹, Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶, Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ andAr⁵⁰ may have a substituent, whose examples may be the same as those ofR¹¹ described above. Ar⁴¹, Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶, Ar⁴⁷, Ar⁴⁸,Ar⁴⁹ and Ar⁵⁰ are not bonded to each other to form a ring. Each of Ar⁴¹,Ar⁴², Ar⁴³, Ar⁴⁴, Ar⁴⁵, Ar⁴⁶, Ar⁴⁷, Ar⁴⁸, Ar⁴⁹ and Ar⁵⁰ is preferably anaryl group, more preferably a phenyl group, a naphthyl group, an anthrylgroup, a pyrenyl group or a phenanthryl group, most preferably a phenylgroup.

In the general formula (5), each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴ representsan aryl group, preferably a phenyl group, a naphthyl group, an anthrylgroup, a phenanthryl group or a fluoranthenyl group, more preferably aphenyl group, a naphthyl group, an anthryl group or a phenanthryl group,further preferably a phenyl group, a naphthyl group or a phenanthrylgroup, most preferably a phenyl group. Each of Ar⁵¹, Ar⁵², Ar⁵³ and Ar⁵⁴may have a substituent, whose examples may be the same as those of R¹¹described above.

In the general formula (5), R⁵¹ represents a hydrogen atom or asubstituent. Examples of the substituents may be the same as those ofR¹¹ described above. R⁵¹ is preferably a hydrogen atom, an alkyl groupor an aryl group, more preferably a hydrogen atom, a phenyl group or apyrenyl group, most preferably a pyrenyl group.

In the general formula (5), R⁵² represents a substituent, whose examplesmay be the same as those of R¹¹ described above. R⁵² is preferably analkyl group or an aryl group. n⁵¹ represents the number of R⁵², which isan integer of 0 to 9, preferably 0 to 2, more preferably 0. The numberof pyrenyl groups in the compound represented by the general formula (5)is preferably two or less.

In the general formula (6), Ar⁶¹ and Ar⁶⁸ are the same as the aboveAr²¹; Ar⁶² and Ar⁶⁷ are the same as the above Ar²²; Ar⁶³ and Ar⁶⁶ arethe same as the above Ar²³; and Ar⁶⁴ and Ar⁶⁵ are the same as the aboveAr²⁴, in their definitions and preferred examples. Each of Ar⁶¹, Ar⁶²,Ar⁶³, Ar⁶⁴, Ar⁶⁵, Ar⁶⁶, Ar⁶⁷ and Ar⁶⁸ may have a substituent, whoseexamples may be the same as those of R¹¹ described above. Each of n⁶¹and n⁶² represents an integer of 0 to 5, preferably 0 to 3, morepreferably 0 or 1.

In the general formula (6), R⁶¹ and R⁶² are the same as the above R²¹ intheir definitions and preferred examples. R⁶³, R⁶⁴ and R⁶⁵ are the sameas the above R⁵² in their definitions and preferred examples. Each ofn⁶³ and n⁶⁴ represents an integer of 0 to 4, preferably 0 or 1, morepreferably 0. n⁶⁵ represents an integer of 0 to 8, preferably 0 to 2,more preferably 0.

The compound (1) is preferably a low-molecular-weight compound and itmay be an oligomer or a polymer. In a case where the compound (1) is apolymer or an oligomer, its weight-average molecular weight determinedwith polystyrene as a standard is preferably 1,000 to 5,000,000, morepreferably 2,000 to 1,000,000, most preferably 3,000 to 100,000. Thepolymer may contain a moiety represented by the formula (1) in its mainor side chain. The polymer may be a homopolymer or a copolymer.

The compound (1) preferably has the maximum emitting wavelength λ_(max)of 370 to 500 nm in a fluorescence spectrum of its single layer orpowder. λ_(max) is more preferably 390 to 480 nm, further preferably 400to 460 nm, and most preferably 400 to 440 nm.

Each of the compounds represented by the general formula (1), compoundsused in the electron-transporting layer and compounds used in thehole-transporting layer has a glass transition temperature Tg ofpreferably 100° C. or higher, more preferably 120° C. or higher, furtherpreferably 140° C. or higher, particularly preferably 160° C. or higher.

The light-emitting device of the present invention preferably furthercontains at least one fluorescent compound in its light-emitting layer.Within the preferred range of the fluorescent compounds are compoundsdescribed herein as materials for the light-emitting layer and theirderivatives.

Specific examples of the compounds (1) are illustrated below withoutintention of restriction.

The compounds represented by the general formulae (1)-(6) may bepurified. Purification methods are not particularly limited but may be arecrystallization method, a column chromatography method, a sublimationpurification method, etc.

The sublimation purification methods are known, and may be a methoddescribed, for instance, in “Lecture One on Experimental Chemistry,Basic Operations [I]” issued by Maruzen Co., Ltd. pp. 425 to 430,methods described in JP 5-269371 A, JP 6-263438 A, JP 7-24205 A, JP7-204402 A, JP 11-171801 A, JP 2000-93701 A, JP 200048955 A, JP 62-22960B, JP 2583306 B, JP 2706936 B, etc. The sublimation purification may becarried out in vacuum or in a flow of an inert gas such as nitrogen,argon, etc. A vacuum pump for carrying out the sublimation purificationin vacuum is not particularly restrictive, but may be a rotary pump, aturbo molecular pump, a diffusion pump, etc.

The compound (1) may be synthesized by known methods described inTetrahedron, 1997, 53, No. 45, p. 15349; J. Am. Chem. Soc., 1996, 118,p. 741; J. Org. Chem. Soc., 1986, 51, p. 979; Angew. Chem. Int. Ed.Engl., 1997, 36, p. 631; Indian J. Chem. Sect. B, 2000, 39, p. 173; Org.Synth. Coll. Vol. 5, 1973, p. 604; Chem. Ber., 1960, 93, p. 1769, etc.

Although the light-emitting device of the present invention is notparticularly limited with respect to a system and a driving methodtherefore, use thereof, etc., the light-emitting device preferably has astructure that uses the compound (1) as a light-emitting material, or asa host material, an electron-injecting material, anelectron-transporting material, a hole-injecting material and/or ahole-transporting material. Typically known as the light-emittingdevices are organic electroluminescence (EL) devices.

The light-emitting device of the present invention comprises alight-emitting layer and a plurality of organic layers comprising alight-emitting layer between a pair of electrodes (a positive electrodeand a negative electrode). The light-emitting layer or at least one ofthe organic layers comprises the compound (1). When the compound of thepresent invention is used as a light-emitting material, the amount ofthe compound (1) in the layer comprising the compound (1) is preferably0.1 to 100% by mass, more preferably 0.5 to 100% by mass. When thecompound (1) is used as a host material, the amount of the compound (1)is preferably 10 to 99.9% by mass, more preferably 20 to 99.5% by mass.

The formation of a layer comprising the compound (1) is not particularlylimited, and the layer may be formed by a resistance-heating vapordeposition method, an electron beam method, a sputtering method, amolecular-stacking method, a coating method, an inkjet-printing method,a printing method, a transferring method, an electrophotography method,etc. Preferable among them are a resistance-heating vapor depositionmethod, a coating method and a printing method from the viewpoints ofproperties and production cost of the light-emitting device.

The light-emitting device of the present invention may comprisefunctional layers such as a hole-injecting layer, a hole-transportinglayer, an electron-injecting layer, an electron-transporting layer, aprotective layer, etc., in addition to the light-emitting layer. Thefunctional layers may have other functions. The compound (1) may becontained in any of these layers. Each component of the light-emittingdevice of the present invention is described in detail below.

(A) Positive Electrode

The positive electrode acts to supply holes to the hole-injecting layer,the hole-transporting layer, the light-emitting layer, etc. The positiveelectrode is generally made of a pure metal, an alloy, a metal oxide, anelectrically conductive compound, a mixture thereof, etc., preferablymade of a material having a work function of 4 eV or more. Examples ofmaterials for the positive electrode include metals such as gold,silver, chromium nickel and these alloys; electrically conductive metaloxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide(ITO); mixtures and laminations of the metals and the electricallyconductive metal oxides; electrically conductive inorganic compoundssuch as copper iodide and copper sulfide; electrically conductiveorganic compounds such as polyaniline, polythiophene and polypyrrole;laminates of the electrically conductive organic compounds and ITO; etc.The positive electrode is preferably made of electrically conductivemetal oxides, particularly ITO, from the viewpoints of productivity,electron conductivity, transparency, etc.

A method for forming the positive electrode may be selected depending onthe material used therefore. For example, the positive electrode made ofITO may be formed by an electron beam method, a sputtering method, aresistance-heating vapor deposition method, a chemical reaction methodsuch as a sol-gel method, a coating method using a dispersion containingindium tin oxide, etc. The positive electrode may be subjected to awashing treatment, etc., to lower the driving voltage, or to increasethe light-emitting efficiency of the light-emitting device. For example,in the case of the positive electrode of ITO, a UV-ozone treatment and aplasma treatment are effective. The positive electrode preferably hassheet resistance of a few hundred Ω/square or less. Although thethickness of the positive electrode may be appropriately determineddepending on the material used therefore, it is in general preferably 10nm to 5 μm, more preferably 50 nm to 1 μm, most preferably 100 to 500nm.

The positive electrode is generally disposed on a substrate made of sodalime glass, non-alkali glass, transparent resins, etc. The glasssubstrate is preferably made of non-alkali glass to reduce ion elution.In the case of using the soda lime glass, a barrier coating of silica,etc. is preferably formed thereon beforehand. The thickness of thesubstrate is not particularly limited as long as it has sufficientstrength. In the case of the glass substrate, the thickness of thesubstrate is generally 0.2 mm or more, preferably 0.7 mm or more.

(B) Negative Electrode

The negative electrode acts to supply electrons to theelectron-injecting layer, the electron-transporting layer, thelight-emitting layer, etc. Materials for the negative electrode may beselected from pure metals, alloys, metal halides, metal oxides,electrically conductive compounds, mixtures thereof, etc., depending onionization potential, stability, adhesion to a layer adjacent to thenegative electrode such as the light-emitting layer, etc. Examples ofmaterials for the negative electrode include alkali metals such as Li,Na and K, and fluorides and oxides thereof; alkaline earth metals suchas Mg and Ca and fluorides and oxides thereof; gold; silver; lead;aluminum; alloys and mixtures of sodium and potassium; alloys andmixtures of lithium and aluminum; alloys and mixtures of magnesium andsilver; rare earth metals such as indium and ytterbium; mixturesthereof; etc. The negative electrode is preferably made of a materialhaving a work function of 4 eV or less, more preferably made ofaluminum, an alloy or a mixture of lithium and aluminum, or an alloy anda mixture of magnesium and silver.

The negative electrode may have a single-layer structure or amulti-layer structure. A preferred multi-layer structure isaluminum/lithium fluoride, aluminum/lithium oxide, etc. The negativeelectrode may be formed by an electron beam method, a sputtering method,a resistance-heating vapor deposition method, a coating method, etc. Aplurality of materials may be simultaneously deposited by the vapordeposition method. The negative electrode of an alloy may be formed bysimultaneously depositing a plurality of metals, or by depositing theiralloy. The negative electrode preferably has a sheet resistance of a fewhundred Ω/square or less. Although the thickness of the negativeelectrode may be appropriately determined depending on the material usedtherefore, it is in general preferably 10 nm to 5 μm, more preferably 50nm to 1 μm, most preferably 100 nm to 1 μm.

(C) Hole-injecting Layer and Hole-transporting Layer

Materials used for the hole-injecting layer and the hole-transportinglayer are not particularly limited as long as they have any functions ofinjecting holes provided from the positive electrode into thelight-emitting layer; transporting holes to the light-emitting layer;and blocking electrons provided from the negative electrode. Theirexamples include carbazole, triazole, oxazole, oxadiazole, imidazole,polyarylalkanes, pyrazoline, pyrazolone, phenylenediamine, arylamines,amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone,stilbene, silazane, aromatic tertiary amine compounds, styrylaminecompounds, aromatic dimethylidyne compounds, porphyrin compounds,polysilane compounds, poly(N-vinylcarbazole), aniline copolymers,electrically conductive polymers and oligomers such as oligothiophenesand polythiophenes, organic silane compounds, the compound (1),derivatives thereof, carbon, etc.

Each of the hole-injecting layer and the hole-transporting layer may bea single layer made of one or more materials, or a multi-layer made ofthe same or different materials. The hole-injecting layer and thehole-transporting layer may be formed by a vacuum deposition method, anLB method, a coating method using a solution or a dispersion containingthe above material such as a spin-coating method, a casting method and adip-coating method, an inkjet-printing method, a printing method, atransferring method, an electrophotography method, etc. A solution and adispersion used in the coating method may contain a resin. Examples ofsuch resins include poly(vinyl chloride), polycarbonates, polystyrene,poly(methyl methacrylate), poly(butyl methacrylate), polyesters,polysulfones, poly(phenylene oxide), polybutadiene,poly(N-vinylcarbazole), hydrocarbon resins, ketone resins, phenoxyresins, polyamides, ethyl cellulose, poly(vinyl acetate), ABS resins,polyurethanes, melamine resins, unsaturated polyester resins, alkydresins, epoxy resins, silicone resins, etc. Although the thickness ofeach of the hole-injecting layer and the hole-transporting layer is notparticularly limited, it is in general preferably 1 nm to 5 μm, morepreferably 5 nm to 1 μm, particularly 10 to 500 nm.

(D) Light-emitting Layer

In the light-emitting layer, holes injected from the positive electrode,the hole-injecting layer or the hole-transporting layer and electronsinjected from the negative electrode, the electron-injecting layer orthe electron-transporting layer are recombined to emit light when anelectric field is applied to the light-emitting device. Light-emittingmaterials and fluorescent compounds for the light-emitting layer are notparticularly limited as long as they have functions of receiving holesprovided from the positive electrode, etc.; receiving electrons providedfrom the negative electrode, etc.; transporting charges; and recombiningholes and electrons to emit light when an electric field is applied tothe light-emitting device. Examples of the light-emitting materialsinclude benzoxazole; benzoimidazole; benzothiazole; styrylbenzene;polyphenyl; diphenylbutadiene; tetraphenylbutadiene; naphthalimido;coumarin; perynone; oxadiazole; aldazine; pyralidine; cyclopentadiene;bis(styryl)anthracene; quinacridon; pyrrolopyridine;thiadiazolopyridine; cyclopentadiene; styrylamine; aromaticdimethylidine compounds; pyrromethene; condensed aromatic compounds suchas anthracene, pyrene, fluoranthene, perylene; metal complexes such as8-quinolinol derivative metal complexes; high-molecular-weight,light-emitting materials such as polythiophene, polyphenylene andpolyphenylenevinylene; organic silane compounds; the compound (1);derivatives thereof; etc.

The light-emitting layer may be made of one or more materials. Thelight-emitting device of the present invention may comprise one or morelight-emitting layers. In a case where the light-emitting devicecomprises a plurality of light-emitting layers, each of thelight-emitting layers may be made of one or more materials, and may emitlight with a different color to provide white light. The singlelight-emitting layer may provide white light.

The light-emitting layer may be formed by a resistance-heating vapordeposition method; an electron beam method; a sputtering method; amolecular-stacking method; a coating method such as a spin-coatingmethod, a casting method and a dip-coating method; an inkjet-printingmethod; a printing method; an LB method; a transferring method; anelectrophotography method; etc. Preferable among them are theresistance-heating vapor deposition method and the coating method.Although the thickness of the light-emitting layer is not particularlylimited, it is in general preferably 1 nm to 5 μm, more preferably 5 nmto 1 μm, particularly 10 to 500 nm.

(E) Electron-injecting Layer and Electron-transporting Layer

Materials used for the electron-injecting layer and theelectron-transporting layer are not particularly limited as long as theyhave any functions of injecting electrons provided from the negativeelectrode into the light-emitting layer; transporting electrons to thelight-emitting layer; and blocking holes provided from the positiveelectrode. Examples of such materials include triazole; oxazole;oxadiazole; imidazole; fluorenone; anthraquinodimethane; anthrone;diphenylquinone; thiopyran dioxide; carbodiimide; fluorenylidenemethane;distyrylpyrazine; tetracarboxylic anhydrides having such aromatic ringsas a naphthalene ring and a perylene ring; phthalocyanine; metalcomplexes such as 8-quinolinol derivative metal complexes,metallophthalocyanines and metal complexes containing benzoxazole orbenzothiazole as a ligand; metals such as aluminum, zinc, gallium,beryllium, magnesium; organic silane compounds; the compound (1);derivatives thereof; etc.

Each of the electron-injecting layer and the electron-transporting layermay have a structure of single-layer made of one or more materials, ormulti-layers made of the same or different materials. Theelectron-injecting layer and the electron-transporting layer may beformed by a vacuum deposition method; an LB method; a coating methodusing a solution or a dispersion containing the above material, such asa spin-coating method, a casting method and a dip-coating method; aninkjet-printing method; a printing method; a transferring method; anelectrophotography method; etc. The solution and the dispersion used inthe coating method may contain a resin. Examples of such resins may bethe same as those for the hole-injecting layer and the hole-transportinglayer. Although the thickness of each of the electron-injecting layerand the electron-transporting layer is not particularly limited, it isin general preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm,particularly 10 to 500 nm.

(F) Protective Layer

The protective layer acts to shield the light-emitting device from thepenetration of moisture, oxygen, etc. that deteriorates the device.Examples of materials for the protective layer include metals such asIn, Sn, Pb, Au, Cu, Ag, Al, Ti and Ni; metal oxides such as MgO, SiO,SiO₂, Al₂O₃, GeO, NiO, CaO, BaO, Fe₂O₃, Y₂O₃ and TiO₂; metal fluoridessuch as MgF₂, LiF, AlF₃ and CaF₂; nitrides such as SiN_(x) andSiO_(x)N_(y); polyethylene; polypropylene; polymethyl methacrylate;polyimides; polyureas; polytetrafluoroethylene;polychlorotrifluoroethylene; polydichlorodifluoroethylene; copolymers ofchlorotrifluoroethylene and dichlorodifluoroethylene; copolymers oftetrafluoroethylene and at least one comonomer; fluorine-containingcopolymers having main chains with cyclic structures; moisture-absorbingmaterials having a water absorption of 1% or more; moisture-resistantmaterials having a water absorption of 0.1% or less; etc.

A method for forming the protective layer is not particularly limited.The protective layer may be formed by a vacuum deposition method, asputtering method, a reactive sputtering method, a molecular beamepitaxy (MBE) method, a cluster ion beam method, an ion-plating method,a high-frequency excitation ion-plating method, a plasma polymerizationmethod, a plasma CVD method, a laser CVD method, a thermal CVD method, agas source CVD method, a coating method, a printing method, atransferring method, etc.

The present invention will be specifically described below withreference to Examples without intention of restricting the scope of thepresent invention.

SYNTHESIS EXAMPLE 1

Synthesis of Compound (1-1)

10 ml of o-xylene was added to 0.5 g of 1-ethynylpyrene and 0.85 g oftetraphenylcyclopentadienone and stirred under reflux for 3 hours. Theresultant reaction product solution was cooled to room temperature, and50 ml of methanol was added thereto to precipitate a solid. The solidwas separated by filtration, and purified by a silica gel columnchromatography (hexane/chloroform=5/1), to obtain 1.1 g of a whitesolid. Mass spectrum measurement confirmed that the white solid wasCompound (1-1). This result suggested that Compound (1-1) was obtainedby the following reaction.

SYNTHESIS EXAMPLE 2

Synthesis of Compound (1-47)

50 ml of diphenyl ether was added to 1 g of the following Compound A and1.35 g of tetraphenylcyclopentadienone and stirred under reflux for 30hours. The resultant reaction product solution was cooled to roomtemperature, and 100 ml of methanol was added thereto to precipitate asolid. The solid was separated by filtration, and purified by a silicagel column chromatography (chloroform), to obtain 1.3 g of a whitesolid. Mass spectrum measurement confirmed that the white solid wasCompound (1-47). This result suggested that Compound (1-47) was obtainedby the following reaction.

SYNTHESIS EXAMPLE 3

Synthesis of Compound (1-15)

50 ml of diphenyl ether was added to 1 g of the following Compound B and3 g of tetraphenylcyclopentadienone and stirred under reflux for 10hours. The resultant reaction product solution was cooled to roomtemperature, and 100 ml of methanol was added thereto to precipitate asolid. The solid was separated by filtration, and purified by a silicagel column chromatography (chloroform), to obtain 2.0 g of a whitesolid. Mass spectrum measurement confirmed that the white solid wasCompound (1-15). This result suggested that Compound (1-15) was obtainedby the following reaction.

SYNTHESIS EXAMPLE 4

Synthesis of Compound (1-2)

10 ml of diphenyl ether was added to 0.5 g of the following Compound Cand 0.85 g of tetraphenylcyclopentadienone and the resultant reactionmixture was stirred under reflux for 3 hours. The resultant reactionproduct solution was cooled to room temperature, and 50 ml of methanolwas added thereto to precipitate a solid. The solid was separated byfiltration, and purified by a silica gel column chromatography(hexane/chloroform=5/1), to obtain 1.0 g of a white solid. Mass spectrummeasurement confirmed that the white solid was Compound (1-2). Thisresult suggested that Compound (1-2) was obtained by the followingreaction.

SYNTHESIS EXAMPLE 5

Synthesis of Compound (1-14)

50 ml of diphenyl ether was added to 0.5 g of the following Compound Dand 3 g of tetraphenylcyclopentadienone and stirred under reflux for 10hours. The resultant reaction product solution was cooled to roomtemperature, and 100 ml of methanol was added thereto to precipitate asolid. The solid was separated by filtration, and purified by a silicagel column chromatography (chloroform), to obtain 0.9 g of pale yellowsolid. Mass spectrum measurement confirmed that the pale yellow solidwas Compound (1-14). This result suggested that Compound (1-14) wasobtained by the following reaction.

Compounds b-v used in the following Examples and Comparative Exampleswill be illustrated below.

Comparative Example 1

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. The above distyryl compound (Compound b) wasvapor-deposited in a thickness of 20 nm thereon, and the above azolecompound (Compound c) was then vapor-deposited in a thickness of 40 nmthereon. With a mask patterned for a desired light-emitting area of 4mm×5 mm disposed on the resultant organic thin film, magnesium andsilver were co-deposited at a mass ratio of magnesium/silver of 10:1 ina thickness of 50 nm on the organic thin film in the depositionapparatus, and silver was further vapor-deposited in a thickness of 50nm thereon, to produce a light-emitting device.

DC voltage was applied to the light-emitting device of ComparativeExample 1 by “Source-Measure Unit 2400” available from Toyo Corporationto make it emit light, and the emitted light was measured with respectto luminance by “Luminance Meter BM-8” available from TopconCorporation, and emission wavelength by “Spectral Analyzer PMA-11”available from Hamamatsu Photonics K. K. As a result, it was found thatthe light-emitting device of Comparative Example 1 emitted bluish greenlight with a chromaticity of (0.15, 0.20) at the maximum luminance of1,130 cd/m². After leaving this light-emitting device in a nitrogenatmosphere for one day, the layer surface of the light-emitting devicelooked clouded.

Example 1

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film, magnesium and silver were co-deposited at a massratio of magnesium/silver of 10:1 in a thickness of 50 nm on the organicthin film in the deposition apparatus, and silver was furthervapor-deposited in a thickness of 50 nm thereon, to produce alight-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted blue light with achromaticity of (0.15, 0.10) at the maximum luminance of 4,370 cd/m².The external quantum efficiency of this light-emitting device wasφ_(EL)=1.4% in a calculated value. After leaving this light-emittingdevice in a nitrogen atmosphere for one day, the layer surface of thelight-emitting device looked transparent.

Example 2

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-17) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) wasvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film magnesium and silver were co-deposited at a mass ratioof magnesium/silver of 10:1 in a thickness of 50 nm on the organic thinfilm in the deposition apparatus, and silver was further vapor-depositedin a thickness of 50 nm thereon, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.15, 0.14) at themaximum luminance of 2,920 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=1.3% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 3

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-24) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) wasvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film, magnesium and silver were co-deposited at a massratio of magnesium/silver of 10:1 in a thickness of 50 nm on the organicthin film in the deposition apparatus, and silver was furthervapor-deposited in a thickness of 50 nm thereon, to produce alight-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted blue light with achromaticity of (0.15, 0.18) at the maximum luminance of 2,000 cd/m².The external quantum efficiency of this light-emitting device wasφ_(EL)=1.3% in a calculated value. After leaving this light-emittingdevice in a nitrogen atmosphere for one day, the layer surface of thelight-emitting device looked transparent.

Example 4

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and7,4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM)were co-deposited in a thickness of 20 nm at a mass ratio of Compound(1-1)/DCM of 1000:5 thereon, and the azole compound (Compound c) wasvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film, magnesium and silver were co-deposited at a massratio of magnesium/silver of 10:1 in a thickness of 50 nm on the organicthin film in the deposition apparatus, and silver was furthervapor-deposited in a thickness of 50 nm thereon, to produce alight-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted white light with achromaticity of (0.30, 0.32) at the maximum luminance of 4,300 cd/m².The external quantum efficiency of this light-emitting device wasφ_(EL)=2.2% in a calculated value. After leaving this light-emittingdevice in a nitrogen atmosphere for one day, the layer surface of thelight-emitting device looked transparent.

Example 5

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Tris(8-hydroxyquinolinato) aluminum (Alq) and DCMwere co-deposited in a thickness of 5 nm at a mass ratio of Alq/DCM of100:1 thereon, and Compound (1-1) was further vapor-deposited in athickness of 15 nm thereon. The azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film, magnesium and silver were co-deposited at a massratio of magnesium/silver of 10:1 in a thickness of 5 nm on the organicthin film in the deposition apparatus, silver was furthervapor-deposited in a thickness of 50 nm thereon, to produce alight-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted white light with achromaticity of (0.31, 0.33) at the maximum luminance of 4,400 cd/m².The external quantum efficiency of this light-emitting device wasφ_(EL)=2.3% in a calculated value. After leaving this light-emittingdevice in a nitrogen atmosphere for one day, the layer surface of thelight-emitting device looked transparent.

Example 6

40 mg of poly(N-vinylcarbazole), 12 mg of2-(4-t-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole and 1 mg of Compound(1-1) were dissolved in 2.5 ml of dichloroethane. The resultant solutionwas spin-coated to a cleaned ITO substrate under the conditions of 1,500rpm and 20 seconds, to form an organic layer having a thickness of 110nm. With a mask patterned for a desired light-emitting area of 4 mm×5 mmdisposed on the resultant organic thin film, magnesium and silver wereco-deposited at a mass ratio of magnesium/silver of 10:1 in a thicknessof 50 nm on the organic thin film in the deposition apparatus, silverwas further vapor-deposited in a thickness of 50 nm thereon, to producea light-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted blue light with achromaticity of (0.15, 0.10) at the maximum luminance of 1,900 cd/m².

Example 7

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-15) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. With a mask patternedfor a desired light-emitting area of 4 mm×5 mm disposed on the resultantorganic thin film, magnesium and silver were co-deposited at a massratio of magnesium/silver of 10:1 in a thickness of 50 nm on the organicthin film in the deposition apparatus, and silver was furthervapor-deposited in a thickness of 50 nm thereon, to produce alight-emitting device. With respect to the light emitted from thislight-emitting device, luminance and emission wavelength were measuredin the same manner as in Comparative Example 1. As a result, it wasfound that the light-emitting device emitted blue light with achromaticity of (0.16, 0.08) at the maximum luminance of 3,200 cd/m².The external quantum efficiency of this light-emitting device wasφ_(EL)=1.2% in a calculated value. After leaving this light-emittingdevice in a nitrogen atmosphere for one day, the layer surface of thelight-emitting device looked transparent.

Example 8

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-2) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) wasvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.16, 0.08) at themaximum luminance of 1,400 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=1.5% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 9

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.17, 0.17) at themaximum luminance of 6,470 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=3.4% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 10

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-14) was vapor-deposited in a thicknessof 20 nm thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.16, 0.17) at themaximum luminance of 2,500 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=0.8% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 11

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) was vapor-deposited in a thicknessof 20 nm thereon, and Compound d was then vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 8 V applied,the light-emitting device emitted blue light of 1,100 cd/m².

Example 12

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) was vapor-deposited in a thicknessof 20 nm thereon, and Compound e was further vapor-deposited in athickness of 40 nm thereon. A negative electrode was vapor-deposited onthe resultant organic thin film in the same manner as in ComparativeExample 1, to produce a light-emitting device. With a voltage of 9 Vapplied, the light-emitting device emitted blue light of 1,300 cd/m².

Example 13

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) was vapor-deposited in a thicknessof 20 nm thereon, and Compound f was vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 9 V applied, thelight-emitting device emitted blue light of 1,200 cd/m².

Example 14

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound g were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound g of100:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted orange light of 2,500 cd/m².

Example 15

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound h were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound h of100:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 7 V applied,the light-emitting device emitted red light of 1,800 cd/m².

Example 16

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound i were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound i of100:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 7 V applied,the light-emitting device emitted green light of 6,300 cd/m².

Example 17

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-2) and Compound j were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-2)/Compound j of100:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 7 V applied,the light-emitting device emitted yellow green light of 4,500 cd/m².

Example 18

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound k were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound k of100:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 7 V applied,the light-emitting device emitted yellow light of 3,900 cd/m².

Example 19

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound m were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound m of10:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 8 V applied,the light-emitting device emitted blue light of 2,800 cd/m².

Example 20

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound m were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound m of1:10 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 8 V applied,the light-emitting device emitted bluish green light of 3,400 cd/m².

Example 21

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound n were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound n of 1:1thereon, and Compound c was further vapor-deposited in a thickness of 40nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 8 V applied, thelight-emitting device emitted blue light of 1,100 cd/m².

Example 22

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound o were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound o of10:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 8 V applied,the light-emitting device emitted blue light of 1,800 cd/m².

Example 23

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound p were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound p of20:1 thereon, and Compound c was further vapor-deposited in a thicknessof 40 nm thereon. A negative electrode was vapor-deposited on theresultant organic thin film in the same manner as in Comparative Example1, to produce a light-emitting device. With a voltage of 8 V applied,the light-emitting device emitted blue light of 3,800 cd/m².

Example 24

Compound q was vapor-deposited in a thickness of 40 nm on a cleaned ITOsubstrate placed in a deposition apparatus. Compound (1-1) wasvapor-deposited in a thickness of 20 nm thereon, and Compound c wasfurther vapor-deposited in a thickness of 40 nm thereon. A negativeelectrode was vapor-deposited on the resultant organic thin film in thesame manner as in Comparative Example 1, to produce a light-emittingdevice. With a voltage of 8 V applied, the light-emitting device emittedblue light of 2,100 cd/m².

Example 25

Compound r was vapor-deposited in a thickness of 10 nm on a cleaned ITOsubstrate placed in a deposition apparatus.N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 30 nm thereon, and Compound (1-1) was thenvapor-deposited in a thickness of 20 nm thereon. Compound c was furthervapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With a voltage of 6 V applied, the light-emitting device emitted bluelight of 2,200 cd/m².

Example 26

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound (1-2) wereco-deposited in a thickness of 20 nm at a mass ratio of Compound(1-1)/Compound (1-2) of 1:1 thereon, and Compound c was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With a voltage of 8 V applied, the light-emitting device emitted bluelight of 2,200 cd/m².

Example 27

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound d and Compound k were co-deposited in athickness of 5 nm at a mass ratio of Compound d/Compound k of 100:1thereon, and Compound (1-1) and Compound p were then co-deposited in athickness of 20 nm at a mass ratio of Compound (1-1)/Compound p of 20:1thereon. Compound c was further vapor-deposited in a thickness of 20 nmthereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 8 V applied, thelight-emitting device emitted white light of 4,100 cd/m².

Example 28

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-14) and Compound p were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-14)/Compound p of20:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 8 V applied, thelight-emitting device emitted blue light of 2,900 cd/m².

Example 29

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-14) and Compound m were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-14)/Compound m of1:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 8 V applied, thelight-emitting device emitted blue light of 3,700 cd/m².

Example 30

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1), Compound p and Compound g wereco-deposited in a thickness of 20 nm at a mass ratio of Compound(1-1)/Compound p/Compound g of 100:5:0.2 thereon, and Compound c wasthen vapor-deposited in a thickness of 40 nm thereon. A negativeelectrode was vapor-deposited on the resultant organic thin film in thesame manner as in Comparative Example 1, to produce a light-emittingdevice. With a voltage of 8 V applied, the light-emitting device emittedwhite light of 1,800 cd/m².

Example 31

A cleaned ITO substrate was spin-coated with “Baytron P” (solution ofPEDOT-PSS, poly(ethylenedioxythiophene) doped with polystyrene sulfonicacid, available from BAYER AG.) under the conditions of 1,000 rpm and 30seconds, and vacuum-dried at 150° C. for 1.5 hours, to form an organiclayer having a thickness of 70 nm. An organic layer thus obtained wasspin-coated with a mixture of 10 mg of polymethyl methacrylate and 30 mgof Compound (1-1) in 4 ml of dichloroethane under the conditions of1,500 rpm and 20 seconds, to form an organic layer having a totalthickness of 120 nm Compound c was vapor-deposited in a thickness of 50nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 10 V applied, thelight-emitting device emitted blue light of 800 cd/m².

Example 32

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) was vapor-deposited in a thicknessof 20 nm thereon, and Compound d was then vapor-deposited in a thicknessof 40 nm thereon. LiF was vapor-deposited in a thickness of 3 nm on theresultant organic thin film, and aluminum was then vapor-deposited in athickness of 100 nm, to produce a light-emitting device. With a voltageof 8 V applied, the light-emitting device emitted blue light of 1,300cd/m².

Example 33

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-2) and Compound s were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-2)/Compound s of100:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted green light of 2,500 cd/m².

Example 34

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-2) and Compound t were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-2)/Compound t of 1:1thereon, and Compound c was then vapor-deposited in a thickness of 40 nmthereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted blue light of 1,500 cd/m².

Example 35

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound u were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound u of100:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted green light of 2,700 cd/m².

Example 36

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound v were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound v of100:1 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 8 V applied, thelight-emitting device emitted reddish orange light of 2,200 cd/m².

Example 37

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-61) and Compound p were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-61)/Compound p of100:2 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted blue light of 1,000 cd/m².

Example 38

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-65) and Compound s were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-65)/Compound s of100:2 thereon, and Compound c was then vapor-deposited in a thickness of40 nm thereon. A negative electrode was vapor-deposited on the resultantorganic thin film in the same manner as in Comparative Example 1, toproduce a light-emitting device. With a voltage of 7 V applied, thelight-emitting device emitted blue light of 1,100 cd/m².

Example 39

N,N′-diphenyl-N,Nα-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-2) and Compound p were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-2)/Compound p of95:5 thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.16, 0.18) at themaximum luminance of 17,000 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=4% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 40

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound p were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound p of95:5 thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.16, 0.20) at themaximum luminance of 10,000 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=3.5% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 41

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-47) and Compound p were co-depositedin a thickness of 20 nm at a mass ratio of Compound (1-47)/Compound p of99:1 thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.16, 0.18) at themaximum luminance of 12,000 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=3.5% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

Example 42

N,N′-diphenyl-N,N′-di(α-naphthyl)benzidine (α-NPD) was vapor-depositedin a thickness of 40 nm on a cleaned ITO substrate placed in adeposition apparatus. Compound (1-1) and Compound p were co-deposited ina thickness of 20 nm at a mass ratio of Compound (1-1)/Compound p of95:5 thereon, and the azole compound (Compound c) was thenvapor-deposited in a thickness of 40 nm thereon. A negative electrodewas vapor-deposited on the resultant organic thin film in the samemanner as in Comparative Example 1, to produce a light-emitting device.With respect to the light emitted from this light-emitting device,luminance and emission wavelength were measured in the same manner as inComparative Example 1. As a result, it was found that the light-emittingdevice emitted blue light with a chromaticity of (0.15, 0.22) at themaximum luminance of 13,000 cd/m². The external quantum efficiency ofthis light-emitting device was φ_(EL)=3.3% in a calculated value. Afterleaving this light-emitting device in a nitrogen atmosphere for one day,the layer surface of the light-emitting device looked transparent.

APPLICABILITY IN INDUSTRY

As described above in detail, the light-emitting device of the presentinvention exhibits excellent light-emitting efficiency, light-emittingproperties, durability, heat resistance and amorphousness with lesslikelihood of being crystallized. The light-emitting device of thepresent invention having such characteristics can be used as a bluelight-emitting device or a white light-emitting device with high colorpurity useful for indicating elements, displays, backlights,electrophotography, illumination light sources, recording light sources,exposing light sources, reading light sources, signs and marks,signboards, interiors, optical communications devices, etc. The compound(1) used in the light-emitting device of the present invention can beused as a material for organic EL devices, and be further applied tomedical applications, fluorescent-whitening agents, materials forphotography, UV-absorbing materials, laser dyes, dyes for color filters,color conversion filters, organic semiconductor materials, electricallyconductive organic materials, etc.

1. A light-emitting device comprising a pair of electrodes and alight-emitting layer or a plurality of organic layers comprising alight-emitting layer disposed between said electrodes, saidlight-emitting layer or at least one of a plurality of organic layerscomprising said light-emitting layer comprising at least one compoundrepresented by the following general formula (6):

wherein each of Ar⁶¹, Ar⁶² , Ar⁶³, Ar⁶⁴, Ar⁶⁵, Ar⁶⁶, Ar⁶⁷ and Ar⁶⁸ isselected from the group consisting of a phenyl group, a napthyl groupand a phenanthryl group; Ar⁶¹, Ar⁶², Ar⁶³ and Ar⁶⁴ are not bonded toeach other to form a ring and Ar⁶⁵, Ar⁶⁶, Ar⁶⁷ and Ar⁶⁸ are not bondedto each other to form a ring; each of R⁶¹ and R⁶² represents a hydrogenatom or a substituent; each of n⁶¹ and n⁶² represents and integer of 0to 5; each of n⁶³ and n⁶⁴ represents 0; and n⁶⁵ represents
 0. 2. Thelight-emitting device of claim 1, wherein in said general formula (6),each of R⁶¹ and R⁶² is selected from the group consisting of a hydrogenatom, a phenyl group and a pyrenyl group.
 3. The light-emitting deviceof claim 1, wherein in said general formula (6), each of n⁶¹ and n⁶²represents 0 or
 1. 4. The light-emitting device of claim 1, wherein insaid general formula (6), each of n⁶¹ and n⁶² represents
 0. 5. Thelight-emitting device of claim 1, wherein in said general formula (6),each of Ar⁶¹, Ar⁶², Ar⁶³, Ar⁶⁴, Ar⁶⁵, Ar⁶⁶, Ar⁶⁷ and Ar⁶⁸ represents aphenyl group.